OpenStack topic endpoints are automatically registered into Redis for discovery across the cloud by OpenStack service daemons.

0mq is only supported with OpenStack Kilo or better; earlier versions of the 0mq support in OpenStack are either incomplete or have bugs.

Configuration

By default, this charm must be deployed alongside Redis for topic discovery, however it can be configured to manage the list of topics via its peer relation:

juju set openstack-zeromq use-local-matchmaker=true

Note that this is only suitable for smaller deployments - all OpenStack service units will propagate topic endpoints via the peer relation, resulting in a large number of hook executions prior to topic configuration being complete in larger clouds.

Limitations

The Oslo Messaging driver for 0mq is know to not work with Cinder multi-backend configurations.

(boolean)
By default, the ZeroMQ driver for OpenStack must
be related to Redis for topic registration and
discovery.
.
Enable this option for use in smaller deployments
to avoid the requirement for Redis; however this
make extensive use of the peer relation and does
not scale well in larger environments.